Implant with hole having porous structure for soft tissue fixation

ABSTRACT

Disclosed herein are an implant with an attachment feature and a method for attaching to the same. The implant may include a cavity with a porous layer disposed within a non-porous layer wherein the non-porous layer defines a chamber. The chamber may receive and confine liquefiable material and direct liquefiable material to permeate through the porous layer. A method of attaching a device to the implant may include liquefying a liquefiable portion of the device and allowing the liquefied material to interdigitate with the second layer and then solidify to prevent pullout.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.15/995,394, filed on Jun. 1, 2018, which claims the benefit of thefiling date of U.S. Provisional Patent Application No. 62/514,318, filedon Jun. 2, 2017, the disclosures of which are hereby incorporated byreference in their entirety.

FIELD OF INVENTION

The present invention relates generally to an implant with an attachmentfeature and a method of attaching to the same, and in particular relatesto an implant with a cavity having a porous structure and a method forattaching to the same.

BACKGROUND OF THE INVENTION

Surgical implants are generally used in repair or reconstruction of bonefractures, defects, tumors, or other maladies. These surgical proceduresmay involve the attachment or reattachment of soft tissue to locationsin the body, such as to the surgical implant itself. For example,surgical procedures in the proximal tibia, proximal femur, and shouldermay involve repositioning soft tissue and even attaching it to theimplant for a successful reconstruction procedure.

Soft tissues are typically attached to implants by sutures, oftenthrough suture openings located on the implant. By way of example butnot limitation, a fracture occurring in the proximal region of thehumerus may require a shoulder stem prosthesis cemented into the humeralmedullary canal. The prosthesis may include multiple suture holes bywhich soft tissues, such as various tendons of the rotator cuff, can besecured to the prosthesis. Attaching sutures to an implant may requireconsiderable time, skill and effort, as it may involve successfullythreading the suture through these suture holes and then securing thesuture to the implant (e.g., by tying a knot in the suture).Manipulation of sutures through the narrow suture holes, which are oftenlocated in tight, inaccessible locations, can be challenging, especiallyduring surgery.

Therefore, there exists a need for an improved implant with attachmentfeatures and a method of attaching to the same.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein are implants with attachment features and methods forattaching to the same.

In a first aspect of the present invention, an implant with one or morecavities is provided. Each cavity may include a first non-porous layerdefining a chamber with an opening, and a second porous layer within thechamber. The chamber may be configured to receive and confineliquefiable material within the chamber and to allow this material topermeate the second layer.

In accordance with the first aspect, the first layer may be shaped tofacilitate permeation of the liquefied material into the second layer byhaving a feature projecting into the chamber to direct the liquefiedmaterial into the second layer. The feature may include a recess havinga second portion of the second layer. The feature may also include atleast one angled side surface to direct liquefied material to the secondlayer.

The implant may include an open passageway extending along an axis fromthe opening to an opposing wall at a distal end of the first surface.The passageway may be surrounded by the second layer and may define aconical shape. The chamber may also be shaped according to any of acylinder, cuboid, cube, cone, and pyramid. In some aspects, the secondlayer may be in communication with the open passageway at the distal endand may extend proximally away from the axis.

The implant may further include a device wherein at least a portion ofthe device may contain liquefiable material. The device may be any of asuture anchor, bone anchor and a second implant. A distal end of thedevice may have substantially the same dimension as the open passagewayand may include an open recess at its distal end. The open recess mayhave two arms extending distally. Each arm may include a first and asecond surface converging at a distal end and define a first angle. Thefirst layer may include a feature projecting into the chamber. Thefeature may be at least partially surrounded by a portion of the secondlayer. The feature may include at least one angled side surface directedtowards the portion of the second layer defining a second angle. Thesecond angle may be greater than the first angle to allow the feature todirect the liquefied material into the second layer.

The liquefiable material may be substantially solid in a first state andsubstantially liquid in a second state. The transition from the firststate to the second state may be caused by the application of any ofheat and ultrasonic energy. The liquefiable material may permeate thesecond layer in the second state and subsequently transition to thefirst state upon the removal of any of the heat and ultrasonic energy.

In other aspects, at least one dimension of the chamber may besubstantially greater than the opening and may provide additionalresistance to device detachment from the implant. The second layer maybe a monolithic structure or may include two or more segments. Thecavity may be secured to the implant or may be integral with the implantsuch that the chamber is inseparable from the implant.

In a second aspect of the present invention, an implant having anon-porous first portion is provided. The first portion may define acavity with an opening containing a porous layer. The cavity may includea second porous layer within the cavity. The cavity may be configured toreceive and confine liquefiable material within the cavity and allowthat material to permeate the second layer.

A third aspect of the present invention is a method of attaching aliquefiable material to an implant. A method in accordance with thisaspect of the invention may include the steps of positioning theliquefiable material in a chamber through an opening of the chamber, thechamber being disposed in a cavity of the implant and defined by a firstnon-porous layer with a second porous layer disposed within the chamber,and securing the liquefiable material to the implant by allowing theliquefiable material to interdigitate with the second layer in a liquidstate and then solidify to prevent pullout of the liquefiable materialfrom the implant. The liquefiable material may be contained in at leasta portion of a device.

The method may further include the step of positioning the liquefiablematerial by placing a distal end of the device in the chamber throughthe opening, the liquefiable material being in a solid state andapplying any of heat energy and ultrasonic energy to transition theliquefiable material from a solid to a liquid state. At least a portionof the first layer may be shaped to direct the permeation of theliquefied material into the second layer.

A fourth aspect of the present invention is a method of fabricating animplant including the steps forming the implant by an additivemanufacturing process, the implant having a cavity having a firstnon-porous layer defining a chamber with an opening and a second porouslayer disposed within the chamber.

The method of additive manufacturing the second layer may include thesteps of depositing a first band of a metal powder onto the first layer,scanning a beam so as to melt the metal powder at predeterminedlocations to form a portion of a plurality of porous geometries in theform of predetermined unit cells within the metal powder layer, theporous geometries having a plurality of struts with a length and across-section, depositing at least one additional layer of metal powderonto the first band, and repeating the step of scanning a beam for atleast some of the additional deposited metal powder layers in order tocontinue forming the porous geometries of the second layer.

A fifth aspect of the present invention is a method of fabricating animplant including the steps of forming an implant with a cavity, formingan insert comprising a first non-porous layer defining a chamber havingan opening and a second porous layer disposed within the chamber,attaching and securing the insert to the cavity.

In a sixth aspect of the present invention, an implant with one or morecavities is provided. Each cavity may include a non-porous layerdefining a chamber with an opening. One or more grooves may be disposedaround the chamber. The grooves may define a first dimension and asecond larger dimension. The chamber may be configured to receive andconfine liquefiable material within the chamber to allow this materialto collect within the grooves.

In accordance with this sixth aspect, the grooves may be shaped to forminternal threading. A minor diameter of the internal threading may beequal to the first dimension and a major diameter may be equal to thesecond dimension.

A seventh aspect of the present invention is a method of attaching aliquefiable material to an implant. A method in accordance with thisaspect may include the steps of positioning the liquefiable material ina chamber through an opening of the chamber, the chamber may be disposedin a cavity of the implant and defined by a non-porous layer, one ormore grooves may be disposed around the chamber, each groove may definea first dimension and a second larger dimension, and securing theliquefiable material to the implant by allowing the liquefiable materialto collect within the grooves in a liquid state and then solidify toprevent pullout of the liquefiable material from the material. Theliquefiable material may be contained in at least a portion of a device.

In accordance with this seventh aspect, the grooves may be configured toform internal threading. A minor diameter of the internal threading maybe the same as the first dimension and a major diameter may be equal tothe second dimension. The liquefiable may solidify within the chamberand may be imparted with an external threading corresponding to theinternal threading.

The method may further include the step of removing the liquefiablematerial after it solidifies from the chamber by unscrewing theliquefiable material to threadingly disengage from the internalthreading.

In an eight aspect of the present invention, an implant with one or morecavities is provided. Each cavity may include a first non-porous layerdefining a chamber with an opening, and a second porous layer within thechamber. The chamber may be configured to receive and confine softtissue within the chamber and to allow soft tissue to permeate thesecond layer.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the presentinvention and the various advantages thereof may be realized byreference to the following detailed description, in which reference ismade to the following accompanying drawings:

FIG. 1 is a perspective view of a cavity in an implant in accordancewith an embodiment of the present invention;

FIG. 2A is a side cross-sectional view of the cavity of FIG. 1 alongline A-A;

FIG. 2B is a top cross-sectional view of the cavity of FIG. 2A alongline B-B;

FIG. 2C is a simplified, side cross-sectional view of a distal end of asuture anchor;

FIG. 3A is side cross-sectional view of a cavity according to anotherembodiment of the present invention;

FIG. 3B is a top cross-sectional view of the cavity of FIG. 3A alongline C-C;

FIG. 4A is a side cross-sectional view of a cavity according to anotherembodiment of the present invention;

FIG. 4B is a top cross-sectional view of the cavity of FIG. 4A alongline D-D;

FIG. 5 is a side cross-sectional view of a cavity according to anotherembodiment of the present invention;

FIG. 6 is a side cross-sectional view of a cavity according to anotherembodiment of the present invention;

FIG. 7 is a side cross-sectional view of a cavity according to yetanother embodiment of the present invention;

FIG. 8 is a side cross-sectional view of a cavity according to yetanother embodiment of the present invention;

FIG. 9 is side cross-sectional view of a cavity according to yet anotherembodiment of the present invention;

FIGS. 10A-10C are schematic side cross-sectional views of the implant ofFIG. 1 showing the sequential steps of attaching a device to the cavity;

FIGS. 11A-11C are schematic side cross-sectional views of the implant ofFIG. 9 showing the sequential steps of attaching and detaching a deviceto the cavity;

FIG. 12 is a perspective view of a shoulder implant with a cavity of thepresent invention;

FIG. 13 is a perspective view of a hip implant with a cavity of thepresent invention;

FIG. 14 is a perspective view of a proximal tibial implant with a cavityof the present invention; and

FIG. 15 is a perspective view of a 3-D printed proximal tibial implantwith a suture anchor secured to a cavity of the present invention.

DETAILED DESCRIPTION

Referring now to FIG. 1, there is shown an implant 10 having a cavity100 according to an embodiment of the present invention. Implant 10shown here is only illustrative of various implants that may be providedwith cavity 10. A top surface 108 of cavity 100 lies on the same planeas a top surface 12 of implant 10. Outer surface 106 of cavity 100 maybe attached to the implant or it may be an integral part of implant 10.For example, cavity 100 may be fabricated to be monolithic with theimplant 10, i.e., by an additive manufacturing process, or cavity 100may be fabricated separately and then secured to implant 10.

FIGS. 2A and 2B are side and top cross-sectional views of cavity 100respectively. Cavity 100 includes a non-porous layer 102 having an outersurface 106 and inner surface 116 forming a chamber. In embodimentswhere the outer surface 106 of the cavity is formed as an integral partof the implant 10, there may be no defined outer surface 106 of thecavity 100, as it may be continuous with the surrounding material of theimplant. An opening 110 at a top surface of the cavity 100 providesaccess to the chamber. As best seen in FIG. 1, cavity 100 is generallycylindrical in shape with the corresponding chamber defined by innersurface 116 also being generally cylindrical in shape. An inner porouslayer 104 is disposed within the chamber and around a longitudinal axisL1 extending through opening 110. Porous layer 104 forms an openpassageway 112 extending from opening 110 to an elevated platform 114located at an opposite end of inner surface 116. A first length D1measured at opening 110 is less than a second length D2 defined by thechamber. As used herein the term “chamber” refers to the space enclosedby inner surface 116, i.e., the passageway 112 and the porous layer 104.In this embodiment, the distance between inner surfaces of porous layer104 defining passageway 112 is the same as first length DE Consequently,the passageway 112 serves as a channel to guide an attachment devicefrom opening 110 to platform 114.

A suture (e.g. for attaching soft tissue to the implant 10) may besecured to the cavity 100. For example, the suture (not shown) may besecured to the cavity 100 by a flowable material that is caused to flowwithin the chamber and then solidify, thus anchoring the suture withinthe cavity 100. The suture itself may be positioned within the chamber,such that it becomes embedded in the flowable material when itsolidifies. An example of such a flowable material may be a curablecement or a melted thermoplastic material. Such material(s) may bepoured into the cavity 100 in a flowable state, either before or afterthe suture is positioned within the cavity 100. While it is in aflowable state, the flowable material may spread out within the chamber(which has a larger diameter D2 than the opening 110, as discussedabove), thus anchoring the suture in the cavity 100 by solidifying in aconfiguration which cannot be pulled through the smaller opening 100.Alternatively or additionally, while in the flowable state, the flowablematerial may interdigitate with the porous layer 104, so as to anchorthe suture in the cavity 100 when the material solidifies.

In other alternative embodiments, the flowable material may bepositioned in the cavity 100 in a solid state and then caused totransition to a flowable state before re-solidifying. As an example, asolid thermoplastic component shaped to fit within the passageway 112may be positioned therein, after which at least a portion of thatcomponent can be melted so as to become flowable. Such melting might beinduced by a heating element (e.g., a resistive heating element) incontact with the thermoplastic component, or the thermoplastic componentmay be remotely heated by directing electromagnetic radiation (e.g.,microwaves or infrared waves) at it. That remotely appliedelectromagnetic radiation may be in the form of coherent waves (e.g.,masers or lasers).

In another example, the solid thermoplastic component may be meltedwithin the cavity 100 by application of ultrasonic vibratory energy,such as by using the technique discussed below or those disclosed inU.S. Pat. Nos. 7,335,205 and 8,403,938, the entire disclosures of whichare incorporated herein by reference. Suitable thermoplastic materialsfor forming such solid component to be melted with ultrasonic vibratoryenergy are disclosed in those patents. The meltable component may beformed entirely or partially out of the thermoplastic material andshaped into a solid suture anchor. The suture anchor may also have oneor more passages, channels, and/or apertures for receiving a suturetherethrough so as to secure the suture to the suture anchor. An exampleof a suitable suture anchor design is illustrated in U.S. Design Pat.No. D710,997, the entire disclosure of which is incorporated herein byreference.

In another example, soft tissue material can be introduced directly intopassageway 112 and allowed to grow into porous layer 104 fixating animplant directly to soft tissue. Non-porous layer 102 may be configuredto direct and contain soft tissue growth within the chamber to maximizefixation. Implants may be provided with a first set of cavities toreceive liquefiable material into porous layers and a second set ofcavities to allow soft tissue growth directly into porous layers. Thefirst set of cavities may facilitate initial fixation and the second setof cavities gradually increase and retain fixation by allowing softtissue growth into porous layers.

FIG. 2C is a simplified, side cross-sectional view of a distal end of asuture anchor 200. Suture anchor 20 shown here is only an example of anattachment device that may be secured to cavity 100, and not meant to belimiting in any way. Suture anchor 20 has a thickness measured by adimension D3, which is substantially the same as D1. Therefore, sutureanchor 20 may be guided through opening 110 and along passageway 112 tocontact platform 114. Elevated sides of platform 114 form an angle 118with an inner side of porous layer 104 and define a pocket 120 as bestseen in FIG. 2A. A corresponding angle 26 formed at the distal end ofsuture anchor 20 is smaller than angle 118. This allows distal tip 28 ofsuture anchor 20 to contact a distal tip of pocket 120 when placed inpassageway 112.

The suture anchor 20 is liquefied within the cavity 100 by contactingthe proximal end of the suture anchor 20 with an ultrasonic sonotrodeand using the sonotrode to press the suture anchor 20 distally towardsthe platform 114 while applying ultrasonic vibratory energy to thesuture anchor 20. That vibratory energy preferably creates internalfriction within the suture anchor 20 and/or between the suture anchor 20and the contacting surfaces of the implant 10, such as the surfaces ofthe porous layer 104 alongside the passageway 112 and/or the distalcontact surface (e.g., on platform 114). The ultrasonic melting can becontrolled in part by selecting an appropriate relationship betweendimensions D1 and D3. For example, creating a relatively tight fitwithin the passageway may increase friction (and corresponding melting)along the outer surface of the suture anchor 20. The liquefied materialmay also be directed outwardly, e.g., by the angled surfaces of platform114, so as to distribute and permeate/interdigitate into porous layer104. Furthermore, the inner surface 116 of non-porous layer 102desirably confines the liquefied material within the chamber.Consequently, varying the shape of the chamber may allow for controllingthe liquefied material permeation. Once the energy application isremoved, the interdigitated thermoplastic material cools and transitionsback from liquid to solid state, thereby anchoring suture anchor 20 tocavity 100 and preventing pullout. The solidified material willpreferably span a substantial or the entire width of chamber, i.e.,corresponding to D2, which, due to the narrower opening 110 defined byD1, further aids in anchoring suture anchor 20 and prevents pullout.

FIGS. 3A and 3B are side and top cross-sectional views of cavity 200respectively according to another embodiment. Cavity 200 is similar tocavity 100, and therefore like elements are referred to with similarreference numerals within the 200-series. For instance, cavity 200 alsoincludes a non-porous layer 202 enclosing a chamber with an inner porouslayer 204. However, porous layer 204 includes two segments in thisembodiment with a porous segment 205 centered around longitudinal axisL1. As best seen in FIG. 3B, porous segment 205 is completely surroundedby a band 215 of non-porous layer 202. Liquefiable material received inpassageway 212 will permeate porous layer 204 similar to the permeationof porous layer 104 in cavity 100 described above, but will also includepermeation of the porous segment 205 in this embodiment. An attachmentdevice attached to cavity 200 will be attached to porous segment 205 andaligned along axis L1. Consequently, any pullout force experienced bythe attached device will include a normal force component acting onporous segment 205, and thereby provide additional resistance to devicedetachment from implant 10.

Referring now to FIGS. 4A and 4B, there is shown side and topcross-sectional views respectively of cavity 300 according to anotherembodiment. Cavity 300 is similar to cavity 100, and therefore likeelements are referred to with similar reference numerals within the300-series. Cavity 300 is cuboidal in this embodiment with non-porouslayer 302 forming a chamber that is also cuboidal. Porous layer 304 isdisposed around longitudinal axis L1 to form a square or rectangularshaped passageway 312. All four sides 305 of porous layer 304 convergeat the distal end and are configured to match a distal tip of anattachment device (not shown).

FIGS. 5, 6, 7, and 8 are further illustrations of side cross-sectionalviews of cavities according to other embodiments of the presentinvention. Cavities 400, 500, 600 and 700 shown in FIGS. 5, 6, 7, and 8respectively are similar to cavity 100, and therefore like elements arereferred to with similar reference numerals within the correspondingseries. Referring now to FIG. 5, cavity 400 may be cylindrical orcuboidal with porous structure 404 arranged around longitudinal axis L1to form passageway 412. Passageway 412 uniformly tapers from opening 410to a single point at a distal end of the chamber and may be configuredto match a distal end of an attachment device.

FIG. 6 shows a spherical cavity 500 with non-porous layer 502 defining aspherical chamber. Porous structure 504 is disposed in the chamberaround a central axis L1 forming a cylindrical passageway 512. Elevatedplatform 514 of non-porous layer 502 is located at a distal end ofpassageway 512 and allows liquefied material to uniformly distribute andpermeate porous layer 504.

FIG. 7 shows cavity 600 where the non-porous layer 602 forms asubstantial portion of passageway 612. Porous layer 604 is disposedaround axis L1 and communicates with passageway 612 at a distal end 603of the passageway. Porous layer 604 extends proximally from distal end603 into non-porous layer 600. The maximum width of the chamber isrepresented by dimension DE When liquefied material of an attachmentdevice is introduced in passageway 612, the liquefied material willpermeate through the porous layer and extend proximally from distal end603. When this material solidifies, the solidified material may span allof a portion of length D2 from location 607 to location 607′ as bestshown in FIG. 7. Therefore, the attached device will have an anchoringbase (D2) which is substantially greater than passageway 612 (D1),thereby adding to the pullout resistance of the device from the implant.FIG. 8 shows cavity 700 which is substantially similar to cavity 600.Here, the distal end of passageway 700 terminates in elevated platform714 with sloped surfaces allowing for improved direction of theliquefied material into the porous region 704. As explained in thedescription of cavity 600, any device attached to cavity 700 may have ananchoring base (D2) which is substantially greater than passageway (D1)to add to the pullout resistance of attached device.

Referring now to FIG. 9, there is shown a cross-sectional view of acavity 800 according to another embodiment. Cavity 800 includes anopening 812 disposed within a non-porous layer 802. Non-porous layer 802includes internal screw threads 818 disposed around the inner walls ofopening 812, which allows the opening to function as a screw hole havinga minor diameter D1 and a major diameter D2. As more fully explainedbelow, a suture anchor 90 (shown in FIGS. 11A-11C) can be secured tocavity 800 by causing flowable material in suture anchor 90 to flow andsolidify in opening 812. Solidified suture anchor 90 will thus beimparted with external threads that match internal screw threads 818 andconsequently suture anchor 90 can be threadingly engaged with opening812. Such threaded engagement desirably secures the suture anchor 90 tocavity 800, thus preventing pullout. Threading engagement of suture 90with opening 812 will also allow for removal of suture anchor 90 fromcavity 800 by rotating and threadingly disengaging suture anchor 90 fromcavity 800. Internal screw threads 818 may be configured to control theinteraction between the suture anchor and the cavity. For example,increasing the delta between major diameter D2 and minor diameter D1will maximize pullout resistance, and decreasing the delta between majordiameter D2 and minor diameter D1 will allow for easier removal ofsuture anchor from cavity and minimize time required for solidification.While internal screw threads 818 disposed throughout opening 812 areshown in FIG. 9, other embodiments may have internal threads locatedonly partially around opening 812. Other embodiments may not haveinternal threads but rather projections formed from the non-poroussection that define a first dimension D1 and a larger second dimensionD2, whereby the solidified suture anchor assumes the second dimension D2in at least some portions and therefore cannot be pulled through thesmaller opening(s) D1.

While cavities and chambers having cylindrical, cuboidal and sphericalshapes are described herein, other cavities may be shaped in any otherform such as a cone or a pyramid. Similarly, the passageway may also maybe shaped in any other form and configured to optimize flow andpermeation of the liquid material. Alternatively, the chamber may becompletely filled with a porous layer in other embodiments. The topsurface of the cavity may be covered by an overmold made ofpolyetheretherketone (“PEEK”) or other similar material to protect theattached device from tearing or shearing away from rough or sharp edgesof the implant. Cavities described herein may be used in any implant,such as but not limited to, hip, knee, shoulder and foot implants.Cavities may be suitably located and distributed across the implants toaid in readily securing attachment devices. Attachment devices mayinclude suture anchors, bone anchors, bone screws, other implants, andother similar devices.

The non-porous layer of the present disclosure may be but is not limitedto being made of any polymer such as PEEK, carbon fiber reinforced PEEK,polyaryletherketones (“PAEK”), ultra-high molecular weight polyethylene(“UHMWPE”), metals, or other suitable material (e.g., ceramic) that isbiocompatible and possess sufficient strength and rigidity. The porousstructure may be but is not limited to being made of any of titaniumfoam, titanium alloys, stainless steel, cobalt chrome alloys, tantalumand niobium or other suitable material.

Other aspects of the present invention are methods for attaching adevice to an implant. Referring now to FIGS. 10A-10C, there is shown amethod of attaching a suture anchor 30 to implant 10 having cavity 100.A distal end of suture anchor 30 is positioned in passageway 112 asshown in FIG. 10A. A thickness D4 corresponding to the thickness ofsuture anchor 30 is substantially the same as passageway 112 dimensionD1 defined by porous layer 104 and opening 110 defined by non-porouslayer 102. Consequently, passageway 112 serves as a guide to directsuture anchor 30 through passageway 112 from opening 110 to elevatedplatform 114 as indicated by direction arrows 31. A portion of sutureanchor 30 may be made of a suitable thermoplastic material which maychange from a solid state 32 to a liquid state 34 upon the applicationof energy. For example, the suture anchor 30 may have a thermoplasticouter layer surrounding a core of a different material, such as metal.Alternatively, the entire suture anchor may be made of a thermoplasticmaterial. Once suture 30 anchor is at least partially located inpassageway 112, ultrasonic energy may be applied to suture anchor 30.

As shown in FIG. 10B, the application of ultrasonic energy (as well as,optionally, distally applied pressure) begins to liquefy thermoplasticmaterial of suture anchor 30 around its periphery, i.e., contactsurfaces within cavity 100. Liquefied material 34 at distal tip 40 incontact with elevated platform 114 is forced by the sides of elevatedplatform into porous section 104 as indicated by directional arrow 36.Further liquefaction of suture anchor 30 takes place along contactsurfaces with porous region 104 as indicated by directional arrows 38showing permeation of liquefied material 34. Application of ultrasonicenergy may continue until the entire chamber is filled with liquefiedmaterial 34 or achieves a desired level of permeation short of beingentirely filled. Once the application of ultrasonic energy is stopped,the liquefied material will cool such that it begins to transition backto a solid state 32. The transition to liquid, permeation, andre-transition back to a solid allows liquefied material 34 tointerdigitate with porous layer 102 and form a strong bond. Further, asbest seen in FIG. 10C a solidified portion, now part of suture anchor10, defines a length D2 which is substantially greater than the lengthof opening 110 (D1). This adds to the securement of suture anchor 10 tocavity 100 and prevents backout of suture anchor 10. While anapplication of ultrasonic energy has been discussed here, any other formof energy appropriate to cause melting and/or liquefaction of thematerial in the attachment device may alternatively be used.

FIGS. 11A-11C show a method of attaching a suture anchor 90 to cavity800 according to another aspect of the present invention. A distal endof suture anchor 90 is guided into passageway 812 as shown by directionarrow 814 in FIG. 11A. A thickness D5 corresponding to the thickness ofsuture anchor 90 is substantially the same as minor diameter D1 ofinternal screw threads 818 thereby establishing contact between thesuture anchor 90 and passageway 812. A portion of suture anchor 90 maybe made of a suitable thermoplastic material which may change from asolid state 92 to liquid state 94 upon the application of energy.Similar to suture anchor 30, suture anchor 90 may have a thermoplasticouter layer surrounding a core of a different material, such as metal,or may entirely be made of a thermoplastic material. Once suture 90anchor is at least partially located in passageway 812, ultrasonicenergy may be applied to suture anchor 90. Liquefied material 94 flowsinto the gaps between minor diameter D1 and major diameter D2 as shownby flow arrows 816 in FIG. 11B. Consequently, a distal portion 96 ofsuture anchor 90 conforms and acquires the shape of internal threads818. Once the application of ultrasonic energy is stopped, liquefiedmaterial 94 will cool and transition back to a solid state. Solidifieddistal portion 96 will acquire external threads 820 corresponding tointernal threads 812 with minor diameter D5, which is the same as D1,and major diameter D2. As best seen in FIG. 11C, suture anchor 90 willnow have a proximal portion 92 with dimension D5 and a thicker distalportion 96 with external screw threads 820 ensuring that suture anchor90 is securely attached to cavity 800. If needed, for example becausethe suture needs to be removed or the suture anchor needs to bereplaced, the threads permit the suture anchor 90 to be threadinglydisengaged from cavity 800 by unscrewing the suture anchor frompassageway 812 as indicated by directional arrow 822. While anapplication of ultrasonic energy has been discussed here, any other formof energy appropriate to cause melting and/or liquefaction of thematerial in the attachment device may alternatively be used.

FIGS. 12-15 show exemplary implants with locations for cavities servingas attachment features. FIG. 12 depicts a shoulder implant 50 having ahumeral stem component 54 that can be attached to a glenoid spherecomponent 52. A proximal region 56 of implant 50 may include one or moreof the cavities disclosed herein (not shown) for attachment of softtissue. One or more posts 58 on glenoid sphere component 52 could alsobe attached to one or more appropriately sized cavities (not shown)located on a proximal surface of humeral stem component 54 using theattachment structures and methods disclosed herein. FIG. 13 shows a hipimplant 60 with cavities 100 located on two sides of a femoral neckcomponent 62. Cavities 100 of femoral neck component 62 can be used toattach suture anchors as described above. FIG. 14 is a perspective viewof a proximal tibial implant 70 with cavities 100 located on two sides.FIG. 15 is a 3-D printed proximal tibial implant 80 with suture anchors82 attached to cavities 100. Suture anchors 82 can be secured to implant80 as described above, whereby sutures 84 attached to suture anchors 82are now firmly secured to implant 80. Exemplary implants described hereare merely illustrative of the principles and applications of thepresent invention and as such the attachment features of the presentinvention may be used in conjunction with any implant.

A further aspect of the present invention is a step of manufacturing animplant with the cavity described herein. The implant may be fabricatedwith the cavity being integral to the implant, or the cavity may befabricated separately and then attached to the implant by snap-fitting,gluing, welding or screwing. Any additive manufacturing process such asthree-dimensional (3D) printing or the like may be used to manufacturethe implant and the cavity. Porous layers in the cavity may be atitanium or other metallic foam fabricated by utilizing any of thefollowing additive manufacturing processes: (1) beam overlap fabricationdisclosed in U.S. Patent Publication No. 2004/0191106, (2) tessellatedunit cell fabrication disclosed in U.S. Patent Publication No.2006/0147332, (3) laser and e-beam polymer interdigitation disclosed inU.S. Patent Publication No. 2007/0142914, (4) conformal surfacesfabrication disclosed in U.S. Patent Publication No. 2013/0268085, or(5) mesh and chain mail fabrication disclosed in U.S. Patent PublicationNo. 2012/0156069. The disclosures of all of the above applications andpublications are hereby incorporated by reference herein. The porousstructure may be but is not limited to being made as a single constructthat covers substantially the entire chamber (as shown for example inFIG. 2A), or composed of multiple segments (as shown for example in FIG.3A). Other suitable biocompatible materials as described above may alsobe used depending on the desired porosity of the porous structure.

Furthermore, although the invention disclosed herein has been describedwith reference to particular features, it is to be understood that thesefeatures are merely illustrative of the principles and applications ofthe present invention. It is therefore to be understood that numerousmodifications, including changes in the sizes of the various featuresdescribed herein, may be made to the illustrative embodiments and thatother arrangements may be devised without departing from the spirit andscope of the present invention. In this regard, the present inventionencompasses numerous additional features in addition to those specificfeatures set forth in the paragraphs below. Moreover, the foregoingdisclosure should be taken by way of illustration rather than by way oflimitation as the present invention is defined in the examples of thenumbered paragraphs, which describe features in accordance with variousembodiments of the invention, set forth in the claims below.

The invention claimed is:
 1. An implant having one or more cavities,each cavity comprising: a non-porous first layer defining a chamberhaving an opening; a porous second layer; wherein the second layer isdisposed within the chamber such that when soft tissue is received inthe chamber through the opening, the soft tissue permeates into thesecond layer and is confined within the chamber by the first layer. 2.The implant of claim 1, wherein the chamber includes an open passagewayextending along an axis from the opening towards an opposing wall, thesecond layer surrounding the open passageway about the axis.
 3. Theimplant of claim 1, wherein the chamber includes an open passagewayextending along an axis from the opening towards and opposing wall at adistal end, the second layer being in communication with the openpassageway at the distal end and extending proximally and away from theaxis.
 4. The implant of claim 1, wherein at least a portion of the firstlayer is shaped to direct the permeation of the soft tissue into thesecond layer.
 5. The implant of claim 4, wherein the first layerincludes a feature projecting into the chamber, the feature being atleast partially surrounded by a portion of the second layer, such thatthe feature directs the soft tissue into the portion of the secondlayer.
 6. The implant of claim 5, wherein the feature includes at leastone angled side surface directed towards the portion of the secondlayer.
 7. The implant of claim 1, further comprising a device whereinthe soft tissue is a portion of the device.
 8. The implant of claim 7,wherein the device is any of a suture anchor, bone anchor and a secondimplant.
 9. The implant of claim 8, wherein a distal end of the devicehas substantially the same dimension as the open passageway.
 10. Theimplant of claim 8, wherein the device is a suture anchor having an openrecess defined at its distal end, the recess being defined by two armsextending distally, each arm comprising of a first and a second surfaceconverging at a distal end and defining a first angle, the first layerincluding a feature projecting into the chamber, the feature being atleast partially surrounded by a portion of the second layer, such thatthe feature directs the soft tissue into the portion of the secondlayer, the feature including at least one angled side surface directedtowards the portion of the second layer defining a second angle, suchthat the second angle is greater than the first angle.
 11. The implantof claim 1, wherein at least one dimension of the chamber measuredparallel to the opening is substantially the same or greater than theopening.
 12. The implant of claim 1, wherein the chamber is shapedaccording to any of a cylinder, sphere, cuboid, cube, cone and pyramid.13. The implant of claim 1, wherein the first and second layers areintegral to the implant such that the chamber is inseparable from theimplant.